Steem might not have had an ICO but they did launch the blockchain quietly a few times and most of the steem was mined before the introduction of Steemit. There is nothing inherently wrong with the ICO model other than many of the current projects not having any reason to have a token in the first place.
If you are going to do an ICO your token better have some economic value in your project. A prime example of a project with a useful ICO was Maker's MKR. Augur REP is another useful token in the Augur project.
There will be many more ICOs and many more uneducated investors getting involved. There will be a 'bubble'. Be careful and do your research.
RE: Why its good Steemit didnt have ICO and has no Ads - Based on Case of MyCellium